In the past, sample handling systems had a single path carrier that would stop at specified locations as desired for testing. In these single path systems, if retesting or preemptive prioritization of a sample were required, the tube would have to travel around the entire module system to be tested or retested. This resulted in either significant delay in testing and retesting or very complex, expensive carrier routing mechanisms.
An example of a single path sample handling device is disclosed in U.S. Pat. No. 5,876,670 to Mitsumaki. In Mitsumaki, a sample carrier, holding a plurality of test tubes, is transferred to the analyzer modules by a transporting belt driven by a motor. All the sample carriers on the transporting belt pass through the sampling position for the first analyzer module and preferably must be transferred to a receiving position to reach the sampling position for the second analyzer module. When a sample needs to be retested, then the operator returns the sample carrier to the beginning of the transporting belt. An urgent sample supply portion is provided on one end of the belt near the sample supply portion, allowing urgent sample racks to be processed before the general racks. In Mitsumaki, the sample handling system processes samples sequentially along the transporting belt and does not automatically retest samples.
Another example of a prior sample handling system is disclosed in U.S. Pat. No. 5,665,309 to Champseix et al. The Champseix et al. device comprises a holding rack for a plurality of test tubes; a sampling station for sampling the contents of a tube; and a gripping device for withdrawing a tube from a selected position on the rack, bringing the tube to the sampling station and returning the tube back to its selected position. The gripping device moves the individual tubes from a rack to the sampling station. However, the Champseix et al., sample handling device does not disclose a method for automatically retesting samples or processing stat samples.
U.S. Pat. No. 5,260,872 to Copeland discloses an automated testing system for the quality testing of production samples, comprising a loading station for receiving a test tube rack containing a plurality of test tubes; a pipetting station; a bead-drop station; and a robotic device having an arm adapted to pick up a test tube rack from the loading station, move the rack to the pipetting station so the fluids can be pipetted into the test tubes; move the rack to the bead-drop station; and return the rack to the loading station in accordance with a computer program. When the Copeland test tube rack is returned to the loading station the tubes may be removed and disposed of and the rack is then loaded with a fresh set of test tubes. The Copeland system does not accommodate for automatic retesting or testing of stat samples.
In the past, reagents have been loaded manually in an automated testing system with a diagnostic module. Reagent replacement is often required in the middle of testing due to consumption of the reagent in a kit or expiration of a reagent. In addition, a reagent may be needed when the system needs to run more test types, analytes, in a day than there are reagent positions in the analyzer. The manual loading of the reagents often resulted in interruption of testing in process or at least a loss of throughput.